Process analysis units perform quasi-continuous analyses for a quantitative determination of an analyte in water and, for that purpose, comprise one or a plurality of reservoir tanks to store liquids, such as carrier liquids, standard solutions and/or reagents needed in performing a water analysis. Pumps and liquid conduits are provided to transport the liquids in the analysis unit.
Upon depletion of a liquid supply in a reservoir tank, the respective reservoir tank must be refilled. In practical operation, problems are often caused, for example, by accumulations and crystallizations in the liquid conduits or in the liquid-carrying parts of the pumps. In addition to a regular refill or replacement of the reservoir tanks, these problems, as well as normal wear of wearing parts, for example, hoses or hose pumps, cause necessary maintenance work and repair, such as the cleaning and maintenance of pumps, replacement of hoses, etc.